APPENDIX 1.

External view of the specimen A1. Note the surface ornamentation and the gently wavy profile. This specimen has only one nepiont.

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APPENDIX 2.

CT rendering of the three nepionts and the first chambers of specimen A6. Note that two nepionts are on the same plane whereas the third nepiont is tilted. Each of the three proloculus-deuteroloculus couplets builds its own ana-nepionic chamber; then the first two nepionts share some of their nepionic chambers, while those of the third nepionts are still clearly separated. The fusion of the third nepiont with the other two happens from the first neanic chamber (first in light blue). Note how each neanic chamber runs through both planes thus creating T-shape connections.

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APPENDIX 3.

Portion of the external surface of specimen A18. Note the multiple equatorial planes all connected each other. Bryozoans, serpulids and other small shells fragments are visible on some surfaces.

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APPENDIX 4.

CT rendering of all nepionts and all equatorial planes in specimen A18. Note how each chamber runs through all equatorial planes with T-shape connections. Click on image to run.

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APPENDIX 5.

CT rendering of all nepionts and all equatorial planes in specimen A18. Note how each chamber runs through all equatorial planes with T-shape connections. Click on image to run.

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APPENDIX 6.

Close-up of all nepionts and one chamber running through all equatorial planes in specimen A18. Note the T-shape connections. Due to the resolution of the CT used and the size of the specimen, the smallest chamberlets could not be segmented, here only well visible chamberlets are presented.

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APPENDIX 7.

Close-up of all nepionts and one chamber running through all equatorial planes in specimen A18. Note the T-shape connections. Due to the resolution of the CT used and the size of the specimen, the smallest chamberlets could not be segmented, here only well visible chamberlets are presented.

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APPENDIX 8.

CT rendering of the nepionts and the first chambers of specimen A2. Note that the three nepionts share some nepionic and all neanic chambers. These three nepionts built one equatorial layer only.

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APPENDIX 9.

External view of specimen A3. Note the two equatorial layer nicely connected by T-shape connections.

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APPENDIX 10.

CT Rendering of the nepionts and of most of the neanic chambers in specimen A3. Note how each chamber runs through both equatorial planes. Click on image to run.

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